Attachment for drills



Dec. 12, 1944. J. E. BOVEE 2,364,688

ATTACHMENT FOR DRILLS Filed Oct. 25,, 1943 2 Sheets-Sheet mvmon. J E. 6 area ATTORNEY v Patented Dec. 12, 1944- UNITED STATES PATENT OFFICE ATTACHMENT FOR DRILLS Joseph E. Bovee, Seattle, Wash.

Application October 25, 1943, Serial No. 507,636

1 Claim.

This invention relates to drills and particularly to attachments for twist drills for cutting smoothed bottomed counterbores and for regulating the depths to be cut.

In some cases tools have been connected with drills for counterboring, but difliculty has been found in providing a tool which will cut a smooth seat for the counterbore, without leaving a rib or ridge at the intersection of the counterbore and drill hole. Such ribs being caused by the difficulty in adjusting the points of counterboring cutters against the drills so closely that a rib may not be left in practice, and in other cases the rib may be caused by the point of the cutters springing away from the drill when in practice. It will be understood that such ribs or inequalities in the base of countersinks prevent even seating of screwheads therein. Other difficulties have been found in regulating the depths of bores and counterbores to be made by the drill and attachments.

It is therefore an object of this invention to provide a frame with blocks therein for binding against the body of the drill for holding the tool in any desired position and to provide blades beneath the blocks for simultaneously cutting counterbores at the same time that the drill operates. And a particular object is to provide such cutting blades in such shape and adjustment that the lower points thereof will project into opposite flutes of the drill when the blocks are clamped against the drill. And further to provide means for regulating the depths to be formed by the cutters and the drill.

With these and other objects that may be hereinafter stated I have illustratively exemplified my invention by the accompanying drawings of which:

Figure 1 shows a side elevation of the tool and drill complete; Figure 2 shows a right hand end elevation; Figure 3 shows a top plan view; Figure 4 shows a section view on line 4-4 of Fig. 1; Figure 5 represents a perspective View of the frame; Figure 6 shows a section view on line 66 of Fig. 3; Figure 7 shows a view of the drill and the movable block; Figure 8 shows a view on line 88 of Fig. '7; Figure 9 shows a section view on line 9-9 of Fig. 7; Figures 10, 11, and 12 show section lines taken respectively on Fig. 7 on lines I0l!l, |l--ll and l2--l2. Figure 13 is a view of the movable jaw and cutter taken on line l3- I3 of Fig. '7 with the drill removed. Figure 14 shows a view of both cutters and a portion of the frame from a point looking at Figure 1 on a 45 degree angle from the right hand side.

Like characters on the different figures represent like parts.

A represents any ordinary twist drill with helical flutes and lands. B represents generally, a rectangular frame withends l5, and 29, provided with threaded holes I6, and 30', for binding screws l1 and 3| respectively. 0 represents a block for clamping against one side of the drill and having its top extended outwardly andhorizontally with jaws l9 and I9 for a counterbalance and provided with a mortice l8 between them for straddling the end l5, to which it is attached by the screw IT. This block is extended downward along drill adjoining the front edge of a land thereof,

and to provide a spillway for removal of cuttings made by the blade. It will be understood that as the point of the cutter extends in the flute that no rib or ridge will be left in the seat of a countersink made by the cutter.

' D represents generally a block for clamping against the opposite side of the drill. This has extended jaws 26 and 21 for straddling the end 29 of the frame, and is adjustably bound against the drill by set screw 3| and wing 3|. The screw is guided and guides the block by a socket 32 in which the pointof the screw is rotated.

D represents a cutter extending beneath the block D in substantially triangular form and similar to the cutter C, and has an outside cutting edge 34 tapering down from the block to a point 35. The inner edge of the block D is V shaped for fitting over the edge of the drill as indicated by 33, and thus carries the point 35 into the flute of the drill opposite to the point 2| adjoining the front edge of a land for like purpose of providing a smooth seat for the counterbore and for removal of cuttings. Above the point 35 along the edge of the cutter adjacent the drill the cutter body is curved or concaved outwardly as at 36 to provide a space 31 for clearance over the drill land and for spillway for cuttings.

By turning the screw 3| the clamp block D may be tightened for binding the block against the drill for supporting the frame and cutters in any position along the body of the drill as may be desired.

Drills of various sizes may be utilized within bar at suitable distances below the frame by a binding screw '53 in the hole 44 for regulating the depths to be made by the drill and cutters. Having described my invention, I claim -as new:

A pair of cutters for use with a twist drill having flutes and lands thereon along the body there- 'of, means for adjustably connecting the cutters to opposite sides of the drill and tapering downward and inward for cutting counterbores, the lower points of such cutters extended into opposite fiutes on the drill adjoining the front edges of opposite lands, said cutters having their inner edges concaved for extending over lands above the lower points-of the cutters and the front faces thereof curved and fluted for removal of cuttings and to facilitate the rapid formation of smooth based counterbores.

' JOSEPH E. BOVEE. 

